Liquid-level indicator



July 12, 192?.

L. A. MA1-EL LIQUID LEVEL INDICATOR .Filed June 9. 1921 2 sheets-sheet 1 July 129 192K L. A. MAPEL, LIQUID LEVEL INDICA-TOR Fi led uns 9 1921 2 'Sheets-Sheet 2 /h/Penfo. @W9/1s 17. ///apey ratei-.ese July i2, i927. 'f

@unirse vsra res erreur oler-ifea.

LnWIs A. MAPEL, oF sr/LoUIs, ivrrssonn, Assenonfro r-.HnAU'roivrA'rrogAPBLIANG COMPANY, .or sm.v Louis, Missouni, A eonronAmIoN' or MISSOURI..

LIanija-LEVEL INDIGATQR.

Application ld June l9,

This 'inventionrelates to'liquid level indicators.v l

An object 01"' the invention is -to provide an improved instrument in which Vthe indieating device is affected through the medium of a Yconfined column of air that is subjected to pressure oi" liquid in the tank and in which the conined column of airis exposed to atmosphere, as anineident to 'the filling of the tank with liquid. l

Another object of the inventionis to pro'- vide an instrument ofthe character nientioned with novel and efiicient inea-ns for containing a confined column or air to transmit pressurefto the indicating device, and for automatically exposng" the pressure chamber to atmosphere yas an incident to the removal of the 'closure `cap of a liquid 'fuel tank. Y*

Another object of the invention `is to'provide novel and efiicientineans for subjecting the confined column of air to Vpressure of liquid in a tank, so that the confinedcolu'mn of air Willtransmit pressurev to an indicating device to afford visual indication of' the' amountA of liquid contained in the tank.

Various other objects and numerous ad'- vantages will be apparent romthe following `description, reference vbeing made tothe accompanying drawings', in which Fig. 1 is a vieiv diagrammaticalin nature, showing one' embodiment of the invention applied to an automobile.

Fig. Q, is an venlarged view showing some or" the parts in section.

Fig. 3 is a view further enlarged as com# pared with 2, showing the source of the confined column of air.

Fig. 4 shoivsthe face oit `the indicating device. Y i

Fig. 5 is an enlarged View sho-Wing a modified or alternative form of the structure ection with the kliquid tank. 6 is a view showing a urthermodin of theYi-nvention. y T 'is a sectional view' showing parts inv position for-use. 8 is an enlarged view of adetail of this modified forni of the invention.

In the embodiment shown in- Figs. '1, 2 and 3, the li uldsupply tank 1 has an inlet opening through jrvhe top, the border Iof which is equipped with anl internally threaded 'pointer' 1921. serial No'. 476,334.

liange 2. A closure cap 3 is provided 'for l removable V through the flange 2, the closure caphav-ing exterioi` 'threads for -engagem'entwvith the application yWithin the hole threads of the fla-nge. An air vent ,4 'is provided in the cap.- l A Afitting.member is secured Within a hole in the bottom of the tank, said memberv comprsing ,a tubular part 5 extending` through the hole in thegtank Wall and a circumferential flange vivithin-the tank, pressing upon Apacking Washer '7'.

A nut 8 is threaded uponl the outerendj of the tubular portidn 5 l of the viitting member, clamping upon a Washer 9 to secure 'the fitting vmember in rigid position; Y 1

" tube 410' extends upwardly from the fitting -member VWithin the `tank and is :enl closed Within a cap-or housing Y11 having `ar number of holes 12 near its lovver end yand a nuni'ber of holes 13' a considerable rdistance below the closed upper end of'salid cap or housing and below the open' upper end ofthe tube 10. A chamber 141y has afconnect'oi'iy 15- yby which, it is n pivotally sup# ported'kroni the cap 3. vThe.chamber'141 is` small. enough to pass readily through the opening closed bythe' cap 3 whensaid'cap is Withdrawn. The upper en'dwall of'the chaI'nb-er l1liispreferablv conical to itailitate Withdrawal tl-ier'e'ofli trein the tain-k.v The' lower' `end Wall ot the' chamber 14 is providedivitl'i a central"4 openingl to receive the ca-p or hofusing: 11, -said opening being of` somewhat la'frgelr ,diy eter :than itl'he' diametery t' the .cap yor housing 11. lThe opening to the' lower end of? thech'ainb'er levis bordered byia flange 16V extending la short distance upivaic'liliy Within" the chamber.- By' reiferavi'll Vbe seenthaft when the closure cap 3 .is inpositionl'ithe l'ovver -end of the chamber 1.1i isi-above the holes :12 and a considerable'-.eistance belowl the holes 13. 1r

Thev indicating device 17 is mounted position convenient for observat`on'; an'din ease* the invention is used upon'an antonio-j bile, -it is .preferablymounted.upon thejinlstrument board.- comprises a gradiuttedy scale V18, and a 19 ai.ranged ito :respond topressure transmitted tothe indicating 'device through Va tube k20 connecting thev indioatingtdevifce With the fittingy meinberf'Thus'; :th'ef Y confined column ot air is provided from the tank l tothe indicating device, and this con-V fined column of air is subjected to pressure of liquid within the liquid tank. When the chamber 14 is withdrawn from the tank in order to permit the tank to be filled with liquid, or for any other purpose, said chamber is necessari-ly placed in communication with atmosphere.. So, also, if the level of vfla-nge 2 a litting member is located, the

vfrom entering the tube.

same-comprising a cap 21 having a portion threaded eXteriorly for engagement with the threads of the flange 2. The cap 21 eX- tends above the flange 2 and is hollow inside. The c ap is provided with an air vent 22 for the admission of air into the tank but said air vent will not communicate with the hollow interior. A tube 23, supported by the cap 2l, extends downwardly within the tank to a point near the bottom of the tank. Said tube 23 and cap 2l forme-an air chamber, which when' inserted in the liquid within the tank, traps the air within said chamber.

Obviouslyr the'air within said chamber thus provided is compressed by the weight vof the gasoline acting upon it. F or example,

the level of the gasol'ne within the tube 23 comes only to a point slightly above the lower open end of said chamber, the remaining area of the chamber containing air under f pressure corresponding to the height of the gasoline within the tank.

A fitting member 24 is inserted in the bottom of the tank l in a manner to prevent leakage; A trap 25 is connected with the fitting member 24 and provided with a removable drainplug 26. The tube 27 rises from the fitting member 24 within the tank to a point above the top of the tank. The upper end of the tube 27 is provided with a downwardly turned portion 28 for the purpose 'of shedding liquid when the tankV is-filled, the liquid being thereby prevented Withinsaid tube 27 at ali-appropriate distance above the level of the flange 2there is a constriction 29, which prevents liquid fromY entering the tube should the tank be filled to overflowing. However, the end of the tube 27 is open to allow communication between the tube 23 and the interior of said tube 27.

From the trap 25, the tube 30, like the tube20, leads to the indicating device.

In the modification shown on Sheet 2 of the drawings, the liquid supply tank l has a liquid supply opening in its top, bordered yby placed inl the internally threaded flange 2. The closurek cap 3l for the liquid supply opening is threaded eXteriorly for engagement with the threads of the flange 2 and is provided with an air vent 32 for the admission of air into the tank. An appropriately formed tube 33 extends through a hole in the cap 3l, the cap being capablefof rotation around the tube. As shown, the wall of the cap is between the collars 34 on thetube, so that when the cap is secured within the supply opening, the tube will be held down within the liquid tank (Fig. 7) 5 and when the cap is released, the tube may be withdrawn from ythe tank and will support the cap, as shown in Fig. 6. rllhe tube 33 has one end provid ed with a tting 35 pivoted to a. support 36 on the tank, or elsewhere as desired. The end of the tube 33 that extends down within the tank l is provided with a pressure chamber 37 having an opening 38 through the bottom wall thereof, bordered by a flange 39 extending upwardly into said chamber.

A tube 40, having a number of coils 4lV near its rear end, leads from the. lfitting 35 to an indicating device 42, supported in a position convenient'for observation as, for instance, on the instrument board of an automobile. `When the tube- 35 and the chamber' 37 are immersed in the liquid within the tank, the air within said chamber and within said tube is compressed by the weight ofthe gasoline acting upon it. For example, the level of the gasoline within the chamber 37 comes only to slightly above the edge of the flange 39, the remaining area of the chamber containing air under pressure corresponding to the height of the gasoline wit-hinV the tank. Such pressure is transmitted to the indicating device 42 through the confined column of air in the tubes 33 and 40, thus causing the indicating device to indicate the amount of gasoline within the tank. l

The installation and operation of' the quipment shownl in Figs. ltofl is as folowswith the supply opening at the top of the tank. The fitting 5 6 with the packing lli() point p lll.)

washer 7 thereon and the cap or housing 1l,

secured thereto, is passed through the supply opening and inserted in the hole rformed through the bottom of the tank. The fitting is secured in position bythe application of the nut 8 and washer 9,.and is connected with the indicating device on the instrument board, or elsewhere as desired, by the tube 20 and the elbow in connection therewith which provides a confined column of air from the equipment in connection with the tank to the indicating device. The tank is then filled with liquid which rises within the cap or housing 11 vto theupper yWalls of the Y.

lindicating device may ybe provided With a double scale, one of which shows the actual amount of vgasoline vin the tank,- :and `the otherotl Which shows only the ainountvabovc the holes 13 and is used for observing the progress in lling the tank only. The compression chamber which is in connection with part 15, having` been secured to the c losure `cap 3 by the swivel connection ineintioned, is vpassed througlrthe supply opening v ly larger diameter 'than the dianieteiiot the the bottom Wall of said chamber,

and is forced into the liquid, the'capor housing 11 passing tl'irough the opening in KThe closure cap fis `secured'to'position iii the usual Way.. 'if-is the pressure chamber is'i'f'orced down finto the l--liquid varound the cap/or housing 11, liquid which Vhas risen .iii-the cap or housingV to the vtop ofthe holes. 13, as stated, is forced out of the'cap or housing through the holes. 12 lea-ving the pressure chamber le andthe cap lliilled withy airl that is subjected .to j pressure by the vliquid in the tank. The hole through tliebottom wall ofthe pressure chamber 14 is oslig'htcap 11,` permitting pressure of the liquid toact upon thefair Within tliefpressure-cl'iam- .berV as YWell as upon the -airin the cap 11 Which is indirect communication with the open upper end 'of the tube 10.` .Thisaction of 'forcing the liquid out'otlie cap 11 results in 4uniting the twoy ,units ,115 and 11i into a single pressurechamber. Liquid will enter the lower end. o'f'tlie chamber `.11i andthe 1 lower end ot the cap 11 in proportion to thehead ofthe `liquid-in the tank, thussub# jee-ting the confined column ofair in theindieet-ing device lto pressure in proportion to the head oi liquid in the tank andycausing the indicating` device' to indicate suoli head.

The i'lange 16 around the hole inthe ybottoni et the chamberll causes a. liquid seal to be formed for preventing exit olf aiif from the chamber-14, diieto'road vibrations or 'angularity of' the tank. ,i y ,e

The installation l'and Aoperation of the' equipment shovviififn Fig.l isgenerally the 'saine as that described above.. :Ahole .is

similarly formed in the bottom of the tanky v andvithef iittin'g 24 is appliedy as described'.A The trap is then connected to the `fitting 24', atter which the tube 30l'froni the indicat-` ing ldevice is connected With the Ytrapte forma 'confined column of air from the tank I' equipment -to the indicating 'devicej The tube 27 with the dovvnvvardlyy turned end 28 having the constriction 29 therein is attached to .the fitting 24, before the iitting isv Asecured'in place. After these parts have been placed 4in. position, the tank isiilled Withliquid Which cannot pass into the tube 27 because said tube has'its .upper end above theplane ot the flange 2, ras described, and further'because of thelconstriction 29.-and the. resistance of the coniinedai-rK Within the tube. After the tank has been hlled, the closure cap-121 'vvithz` thepressure chamber 2B in.connectiontlierevvith 'is secured in place, the.pressure chamber being forcedA down into the liquid around the tube 27.

The pressure chamber'being air-tighur-it fis apparent that the air Within the chamber is subjected'to pressure ybythe liquid in the tank in proportion to 'the `head of lsuch liquid. Since the pressure chamber 28is indirect `coiiiinunication With the confined column noi'.` air Within they tubes 27 {and 30,'it isv apparenty that such conlined column of air issubjected to the ysaine =piessure,- thereby causing Ytlie, f, indicatingdeviceto indicate the 'head,|oif"`. the liquid in the tank eausingsuch pressure. ,5k

The vent 22, similar toy the v, vent 4.,' pro vides .means forthe adniissionioitA air into thev tank y y vfor afvvell understood purpose.. Itfis clearthat fas :the pressure chamber-23 is forced' f yinto r'its place,ithe liquid that has immersed the tubel 27 is displaced,.leaving the lair -Withiiithe ohainber23- surrounding said tube and subjected to pressurep'by the headp'ot liquid in the tank.

" The installation l of them` equipment shovvn on: Sheet 2"of the drawings comprises ,the

provision of Yan appropriate supportsuoh as 36 for pivotally supporti-ng the fitting; 35.'

rllhe end of one arm of the angula'rtube is securedf to the ritting 35, the other arm of .saidl tube passing through and havin'ggsivivel. connectionA with'l the closure cap 31, as dev scribed.y This permits the closurecap lto. be i turned for removal or Y'attachment Without interference by the tubey in" connection therewith. The lower end ofthearinthatpasses through the closure cap` opens into the pres- 1 sure chamber' -87 thatis yunited 'With'said arm; The -titting 35 is connected vwith the i coiled end e1- otf the tube e0,leadingsyto the"- indicating ldevice* :42, thus providing a conv .tinuous confined column et airfA from x the pressure chamber to'said indicating' device, when'the pressure: chamber is immersed inj the liquid in `the tank. -rlhis immersion subjects the confined column of air yto pres- `sure by. the head of liquid `inthetank, thus causing the indicating device to v.respondto such head. After* the vequipment hasibejen properly mounted rand the ta'nkhasibeen iilled with: liquid, thepressure` chamberl' is orcedl dovvn 'into the E, liquid; iii thegtaiik and the closure cap is secured -in place, thereby subjecting the confined air to .pressure by the head of liquid contained in the y tank. Said pressure is eXerted through the hole 38'in the bottom `of the pressure chambei'. Liquid will be forced through the hole 38 in proportion to the head of the-liquid iii the tank, thus subjecting the confined' column of air to pressure in proportion'to'V the head. The fiange 39 around the hole 38 forms a seal preventing exit of air from the pressure chamber, due to vibrations or angularity of the tank.

F rom the foregoing it is apparent that in each form of the invention the pressure l chambers are eXposedto atomsphere periodi# callyWhenever it lis desired to lill the tank.-

It vis also seen that thisl exposing of the pressure chambers to atmosphere when it is desired to fill the tank occurs automatically as 'an incident tothe removal of the seal cap. This overcomes the necessity of the operator giving any attention to the draining of the 4.pressure chambers which is necessary Vin otherV types of gages.

Periodic exposure4 of the pressure chambers to atmosphere pre.-

vents the encroaching of the gasoline upon i the air Within the chamber and this encroachment .is the cause of the indicating device giving a false indication of the gasoline in the tank. By elimination, therefore, of this encroachment, the indicating device. Will give y as an incident to the fllingof the tanlnav .pressure chamber in Which air is. normally confined said liquid, lan indicating device. communicating With said chamber andre-` spoiisive .tothe varying head of said liquid,

andmeans operatively connected with said element and` cooperating With said chamber when the elementis manipulated toexpose said chamberto the atmosphere. f

2. The combination 'Witih a tank from Which liquid is to be Withdrawn and having a filling opening' provided With a closure, of'

' a pressure chamber in Which air is normally confined by said liquid, an indicating device communicating With said chamber and responsive to the varying head .ofsaid liquid,

and an operative connection between said chamber and said closure, whereby upon removal of said closure said chamber is automatically exposed to the atmosphere. 8. The combination With a tank from which liquid is to be Withdrawn and having a filling opening provided With a closure, of

, a pressure chamber in which air is normally confined by lsaid liquid, anindicatiiig device ywith a ltank froiir communicating with said ,chamber and re.-

and said chamber to so position the chamber as to maintain the air confined therein When said closure is in place but adapted to automatically expose said chamber to the atmosphere when said closure is, manipulated to uncover the tank opening.A

4. The combination With a tank from which liquid is to be Withdrawn and having a filling opening,of a pressure chamber vin which air is normally confinedl by said liquid, an indicating device communicating with said chamber and responsive tothe varying head of said liquid, and a closure having connection to said chamber, and adapted .When in closed. position to 4hold said chamber in place iii the liquid and adapted When opened to automatically retract .said chamber `and expose it to the atmosphere.

5. The combination with a tank from` which liquid is to be Withdrawn and provided ivith a filling opening, ofl anindicating device, meansrfor causing said device to initally. respond to a part of the varying head of said liquid, and means cooperating ivith. said last means for4 causing said de vice Vto finally respond tothe entire varying head of said liquid.l i y 1 `o. The combination with a tank from which liquid is to be lWithdrawn yand pro` vided with a filling opening, ofl an indicatiiigdevice, means for causing said device to vrespond to the varying head of said liquid above a predetermined minimumv While the tank is being filled, and means cooperating With said last means forcausing said device to respond also to the varying head ofsaid liquid below said minimum When the liquid is being Withdrawn from the tank.

n 7. The combination y'with a tank from Which liquid is to be Withdrawn and providedivith a'filling opening," of a pressure chamber in which airis confinedv by said liquid, an indicating device connected Vwith said chamber and responsive to the `vai"j,'fiiig lll) lou f i es head of said liquid, and a movable pressure chamber adapted to be positioned for cooperation With said `first pressure chamber and in Which movable chamber when so `positioned the air is confined by said liquid.

8. The combination With aV tank from Whichliquid is to be Withdrawn and provided With'a filling opening, of a pressure chamber adapted to entrap air in said liquid above a predetermined level therein, an'indicating device connected lWitlisaid chamber and responsive to the varyinghead of said liquid, and a movable pressure chamber adapted to be placed over said first pressure chamber in order to cause said liquid to confine the air in both said predetermined level. n

y9. .The combination With y chambers below which liquid is to loe Withdrawn `and provided with a filling opening, of a pressure chamber iu which air is coi'ined by said liquid at a predetermined level, an indicat- .ing device connected with said chamber and responsive to the varying head of said liquid, a second pressure chamber adapted in order to cause said liquid to confine the air in both cliambersat a still lower leveL and means for moving said second chamber to expose the same to the atmosphere.

LEWIS] ifi. -MAPEL Vtobe placed over Suidv first pressure Chamber f' 

